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www.hannainst.com
This Instrument is in
Compliance with the CE Directives
Instruction Manual
HI 95724C
Free & Total Chlorine
ISM
24
MAN95724C 01/04
www.hannainst.com
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TABLE OF CONTENTS
PRELIMINARY EXAMINATION .............................................................................................. 3
GENERAL DESCRIPTION ......................................................................................................4
ABBREVIATIONS ................................................................................................................ 4
SPECIFICATIONS ................................................................................................................ 5
PRECISION AND ACCURACY .................................................................................................5
PRINCIPLE OF OPERATION ..................................................................................................6
FUNCTIONAL DESCRIPTION .................................................................................................7
GUIDE TO DISPLAY CODES ..................................................................................................9
GENERAL TIPS FOR AN ACCURATE MEASUREMENT ............................................................. 11
MEASUREMENT PROCEDURE ...........................................................................................12
VALIDATION PROCEDURE ................................................................................................. 14
CALIBRATION PROCEDURE ...............................................................................................15
BATTERY REPLACEMENT ..................................................................................................18
ACCESSORIES .................................................................................................................19
WARRANTY .................................................................................................................20
CE DECLARATION OF CONFORMITY ...................................................................................21
HANNA LITERATURE ........................................................................................................ 22
USER NOTES .................................................................................................................23
Dear Customer,
Thank you for choosing a Hanna product. This manual will provide you with the necessary
information for the correct use of the instrument. Please read it carefully before using the meter.
If you need additional technical information, do not hesitate to e-mail us at tech@hannainst.com.
This instrument is in compliance with
directives.
All rights are reserved. Reproduction in whole or in part is prohibited without the written consent
of the copyright owner, Hanna Instruments Inc., Woonsocket, Rhode Island, 02895 , USA.
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USER NOTES
Date Validation Value
(mg/L)
Calibration
yes not
Parameter Code Passed
yes not
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PRELIMINARY EXAMINATION
Please examine this product carefully. Make sure that the instrument is not damaged. If any
damage occured during shipment, please notify your Dealer.
Each HI 95724 Ion Selective Meter is supplied complete with:
• Two Sample Cuvets and Caps
• 9V Battery
• Tissue for wiping cuvets
• Two CAL CHECK™ cuvets (HI 95724-11) with Quality Certificate
• Instruction Manual
• Instrument Quality Certificate and Quick Reference Guide
• Rigid carrying case
Note:save all packing material until you are sure that the instrument works correctly. Any
defective item must be returned in its original packing.
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Hanna publishes a wide range of catalogs and handbooks for an equally wide range of
applications. The reference literature currently covers areas such as:
• Water Treatment
• Process
• Swimming Pools
• Agriculture
• Food
• Laboratory
and many others. New reference material is constantly being added to the library.
For these and other catalogs, handbooks and leaflets contact your dealer or the Hanna
Customer Service Center nearest to you. To find the Hanna Office in your vicinity, check our
home page at www.hannainst.com.
HANNA LITERATURE
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The HI 95724 is an auto diagnostic portable microprocessor meter that benefits from Hanna’s
years of experience as a manufacturer of analytical instruments. It has the advanced optical
system based on a special tungsten lamp and a narrow band interference filter that allows most
accurate and repeatable readings. All instruments are factory calibrated and the electronic and
optical design minimizes the need of frequent calibration.
With the powerful CAL CHECK™ validation function you are able to validate good performance
of your instrument at any time. The validation procedure is extremely user friendly. Just use the
exclusive Hanna ready-made, Nist traceable standards to verify the performance of the instrument
and recalibrate if necessary.
All instruments are splash proof and the lamp and filter units are protected from dust or dirt by
a transparent cup. This makes the instruments fulfill field applications. Display codes aid the
user in routine operation. The meter has an auto-shut off feature that will turn off the instrument
after 10 minutes of non use or after 1 hour if left in the calibration mode.
The meter uses an exclusive positive-locking system to ensure that the cuvet is in the same
position every time it is placed into the measurement cell. It is designed to fit a cuvet with a
larger neck making it easier to add both sample and reagents. The cuvet is made from special
optical glass to obtain best results.
The HI 95724 meter measures the free and total chlorine (Cl2) content in water samples in the
0.00 to 5.00 mg/L (ppm) range. The method is an adaption of the USEPA METHOD 330.5 for
wastewater, and Standard Method 4500-Cl G for drinking water.
The reagents are in
liquid form and are supplied in dropper bottles. The amount of reagent is
precisely dosed to ensure the maximum repeatability.
GENERAL DESCRIPTION
ABBREVIATIONS
°C: degree Celsius
USEPA: US Environmental Protection Agency
°F: degree Fahrenheit
mg/L: milligrams per liter. mg/L is equivalent to ppm (part per million)
mL: milliliter
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Recommendations for Users
Before using these products, make sure that they are entirely suitable for your specific application and for the environment in
which they are used.
Operation of these instruments may cause unacceptable interferences to other electronic equipments, this requiring the operator
to take all necessary steps to correct interferences.
Any variation introduced by the user to the supplied equipment may degrade the instruments' EMC performance.
To avoid damages or burns, do not put the instrument in microwave oven. For yours and the instrument safety do not use or
store the instrument in hazardous environments.
CE DECLARATION OF CONFORMITY
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Range 0.00 to 5.00 mg/L of Cl2 (Free or Total)
Resolution 0.01 mg/L from 0.00 to 3.50 mg/L; 0.10 mg/L above 3.50 mg/L
Precision ±0.03 mg/L @ 1.00 mg/L
Typical EMC Deviation ±0.01 mg/L
Light Source Tungsten lamp with narrow band interference filter @ 525 nm
Light Detector Silicon Photocell
Method Adaptation of the USEPA method 330.5 and Standard Method 4500-Cl G.
The reaction between chlorine and the reagents causes a pink tint in
the sample.
Environment 0 to 50°C (32 to 122°F); max 95% RH non-condensing
Battery Type 1 x 9 volt
Auto-Shut off
After 10' of non-use in measurement mode;
after 1 hour of non-use in calibration mode.
Dimensions/Weight 180 x 83 x 46 mm (7.1 x 3.3 x 1.8")/290 g (10 oz.)
REQUIRED REAGENTS
Code Description Quantity/test
HI 93701A-T DPD1 Indicator 3 drops
HI 93701B-T DPD1 Buffer 3 drops
HI 93701C-T DPD3 Solution 3 drops
SPECIFICATIONS
Precision is how closely repeated measurements
agree with each other. Precision is usually
expressed as standard deviation (SD).
Accuracy is defined as the nearness of a test
result to the true value.
Although good precision suggests good accuracy,
precise results can be inaccurate. The figure
explains these definitions.
In a laboratory using a standard solution of
1.00 mg/L chlorine and a representative lot of
reagents, an operator obtained with a single
instrument a standard deviation of 0.03 mg/L.
PRECISION AND ACCURACY
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HI 95724 is warranted for two years against defects in workmanship and materials when used
for its intended purpose and maintained according to the instructions.
This warranty is limited to repair or replacement free of charge.
Damages due to accident, misuse, tampering or lack of prescribed maintenance are not covered.
If service is required, contact your dealer. If under warranty, report the model number, date of
purchase, serial number and the nature of the failure. If the repair is not covered by the warranty,
you will be notified of the charges incurred.
If the instrument is to be returned to Hanna Instruments, first obtain a Returned Goods
Authorization Number from the Customer Service Department and then send it with shipment
costs prepaid. When shipping any instrument, make sure it is properly packaged for complete
protection.
To validate your warranty, fill out and return the enclosed warranty card within 14 days from the
date of purchase.
WARRANTY
Hanna Instruments reserves the right to modify the design, construction
and appearance of its products without advance notice.
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Absorption of Light is a typical phenomenon of interaction between electromagnetic radiation and
matter. When a light beam crosses a substance, some of the radiation may be absorbed by
atoms, molecules or crystal lattices.
If pure absorption occurs, the fraction of light absorbed depends both on the optical path length
through the matter and on the
physical-chemical characteristics of the substance according to the
Lambert-Beer Law:
-log
I
/I
o
ελc d
or
A ελc d
Where:
-log
I
/I
o
= Absorbance (A)
I
o
= intensity of incident light beam
I
= intensity of light beam after absorption
ελ= molar extinction coefficient at wavelength λ
c = molar concentration of the substance
d = optical path through the substance
Therefore, the concentration "c" can be calculated from the absorbance of the substance as the
other factors are known.
Photometric chemical analysis is based on the possibility to develop an absorbing compound
from a specific chemical reaction between sample and reagents. Given that the absorption of a
compound strictly depends on the wavelength of the incident light beam, a narrow spectral
bandwidth should be selected as well as a proper central wavelength to optimize measurements.
The optical system of Hanna's HI 95 series colorimeters is based on special subminiature
tungsten lamps and narrow-band interference filters to guarantee both high performance and
reliable results.
PRINCIPLE OF OPERATION
Block diagram (optical layout)
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REAGENT SETS
HI 93701-F 300 tests Free Chlorine
HI 93701-T 300 tests Free and 100 test Total Chlorine
HI 93711-D3 DPD3 reagent for 200 tests
OTHER ACCESSORIES
HI 95724-11 CAL CHECK™ Standard Cuvets (1 set)
HI 710009 Blue rubber boot
HI 710010 Orange rubber boot
HI 721310 9V battery (10 pcs)
HI 731318 Tissue for wiping cuvets (4 pcs)
HI 731331 Glass cuvets (4 pcs)
HI 731335 Caps for cuvets (4 pcs)
HI 93703-50 Cuvets cleaning solution (230 mL).
ACCESSORIES
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FUNCTIONAL DESCRIPTION
1) Liquid Crystal Display
2) Cuvet Holder
3) Cuvet alignment indicator
4) ON/OFF key
5) ZERO key
6) READ key
7) CAL CHECK key
A microprocessor controlled special tungsten lamp emits radiation which is first optically
conditioned and beamed to the sample contained in the cuvet. The optical path is fixed by the
diameter of the cuvet. Then the light is spectrally filtered to a narrow spectral bandwidth, to
obtain a light beam of intensity
I
o
or
I
.
The photoelectric cell collects the radiation I that is not absorbed by the sample and converts
it into an electric current, producing a potential in the mV range.
The microprocessor uses this potential to convert the incoming value into the desired measuring
unit and to display it on the LCD.
The measurement process is carried out in two phases: first the meter is zeroed and then the
actual measurement is performed.
The cuvet has a very important role because it is an optical element and thus requires particular
attention. It is important that both the measurement and the calibration (zeroing) cuvets are
optically identical to provide the same measurement conditions. Whenever possible use the same
cuvet for both. It is necessary that the surface of the cuvet is clean and not scratched. This to
avoid measurement interference due to unwanted reflection and absorption of light. It is
recommended not to touch the cuvet walls with hands.
Furthermore, in order to maintain the same conditions during the zeroing and the measuring
phases, it is necessary to close the cuvet to prevent any contamination.
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Battery replacement must only take place in a
non-hazardous area.
Simply slide off the battery cover on the back of
the meter. Detach the battery from the terminals
and attach a fresh 9V battery while paying
attention to the correct polarity. Insert the battery
and replace the cover.
9V
SLIDE
OFF
BATTERY REPLACEMENT
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KEYPAD DESCRIPTION
• ON/OFF: to turn the meter on and off.
• ZERO: press to zero the meter prior to measurement.
• READ: press for making a measurement.
• CAL CHECK: this bi-functional key allows to perform validation of the instrument just pressing
the CAL CHECK key, or hold the key for 3 seconds to enter the calibration mode.
OPERATING MODES
• Measurement mode: default operation mode, enables both validation and measurement.
• Calibration mode: may be entered by keeping CAL CHECK pressed
for three seconds (the “CAL”
icon appears), it enables calibration of the instrument.
DISPLAY ELEMENTS DESCRIPTION
1) four digit main display area.
2) CAL: appears when the instrument operates in the calibration mode.
3) the Month and Day icons appear above the number of month and day when a date is
displayed.
4) the blinking “Battery” icon appears when the battery voltage is getting low.
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FACTORY CALIBRATION RESET
It is possible to restore factory calibration:
DATE INPUT
• Keep READ pressed to scroll to the desired
month number (01-12).
• When the correct month has been set, press
ZERO to confirm.
• Now the display will show the day number
blinking. Keep READ pressed to scroll to the
desired day number (01-31).
Note: it is possible to change from day to month
and vice versa by pressing ZERO.
• When both the day and month have been
selected, hold CAL CHECK
for three seconds
to store date and calibration values. The
instrument will show for one second “Stor”,
to confirm that the new calibration data has
been accepted.
• The instrument will return automatically to
the measurement mode by displaying "724"
on the LCD.
• Enter the calibration mode by holding CAL
CHECK for three seconds.
• Hold ZERO for 10 seconds. The display will
show for 2 seconds “F.CAL” and "724"
appears. The factory calibration is
automatically restored and the instrument is
ready for measurement.
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This prompt appears for 1 second each time the instrument is turned on.
The parameter code “724” indicates that the meter is in a ready state
and zeroing can be performed.
Sampling in Progress. This
flashing prompt appears each time the meter
is performing a measurement.
This indicates that the meter is in a zeroed state and measurement can
be performed.
The blinking "BAT" indicates that the battery voltage is getting low and
the battery needs to be replaced.
This indicates that the battery is dead and must be replaced. Once this
indication is displayed, the meter will lock up. Change the battery and
restart.
“Configuration”: this indicates that the meter has lost its configuration.
Contact your dealer or the nearest Hanna Customer Service Center.
CALIBRATION MODE MESSAGES
The date of the last calibration appears on the LCD each time the
calibration mode is entered. If calibration is performed for the first time,
“F.CAL” appears.
This indicates that the factory calibration is selected.
GUIDE TO DISPLAY CODES
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2
11
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1
The flashing digits indicate that:
1) the month can be set
2) the day can be set
“Storage”: this prompt appears for 1 second at the end of the calibration
procedure, to indicate that the calibration data has been stored.
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or
Note: at this point it is possible to reset the
instrument to restore FACTORY
CALIBRATION, see instructions page 17.
• Place the CAL CHECK™ Standard Cuvet A
into the holder and ensure that the notch on
the cap is positioned securely into the groove.
• Press ZERO and “SIP” will blink on the
display.
• After a few seconds the display will
show “-0.0-”. The meter is now zeroed and
ready for calibration.
• Remove the cuvet and place the CAL CHECK™
Standard HI 95724-11 Cuvet B into the
holder. Ensure that the notch on the cap is
positioned securely into the groove.
• Press READ and “SIP” will blink during
measurement.
• The instrument will show for three seconds
the CAL CHECK™ standard value.
Then the date of last calibration (e.g.:
“01.08”) appears on the display, or “01.01”
if the factory calibration was selected. In
both cases the number of the month is
blinking, ready for date input.
Note:if the display shows “ERR” the calibration procedure failed. Verify that both CAL CHECK™
Standards HI 95724-11 Cuvets, A and B, are free from fingerprints or dirt and that they
are inserted correctly.
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“Error”: the concentration of the calibration solution used is not correct.
Repeat the calibration procedure with the right standard solution, and
verify it is not expired. If the calibration procedure fails again, contact your
dealer or the nearest Hanna Customer Service Center.
ERROR MESSAGES
a) on zero reading
This indicates that the zeroing procedure failed due to a low signal-to-noise
ratio. In this case press ZERO again.
“No Light”: the instrument cannot adjust the light level. Please check that
the sample does not contain any debris.
“Light Low”: there is not enough light to perform a measurement. Please
check the preparation of the zero cuvet.
“Light High”: there is too much light to perform a measurement. Please check
the preparation of the zero cuvet.
b) on sample reading
There is too much light for the sample measurement. Please check if the right
sample cuvet is inserted.
“Inverted”: the sample and the zero cuvet are inverted.
“Zero”: a zero reading was not taken. Follow the instruction in the
measurement procedure for zeroing the meter.
Under range. A blinking "0.00" indicates that the sample absorbs less
light than the zero reference. Check the procedure and make sure you
use the same cuvet for reference (zero) and measurement.
A flashing value of the maximum concentration indicates an over range
condition. The concentration of the sample is beyond the programmed
range: dilute the sample and re-run the test.
A flashing value lower than the maximum concentration indicates a low
signal-to-noise ratio condition. In this case accuracy of the result is not
guaranteed. Repeat the measurement procedure.
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• Remove the cuvet and place the CAL
CHECK™ Standard HI 95724-11 Cuvet B
into the holder. Ensure that the notch on
the cap is positioned securely into the
groove.
• Press CAL CHECK and “SIP” will blink during
measurement.
• Wait for a few seconds and the display will
show the validation standard value.
The reading should be within specifications
as reported on the CAL CHECK™ Standard
Certificate. If the value found is out of
specifications, please check that the cuvets
are free of fingerprints, oil or dirt and
repeat validation. If results are still found
out of specifications then recalibrate the
instrument.
CALIBRATION PROCEDURE
Note: It is possible to interrupt calibration procedure at any time by pressing ON/OFF.
Warning: do not validate or calibrate the instrument with standard solutions other than the Hanna
CAL CHECK™ Standards, otherwise erroneous results will be obtained. For accurate Validation and
Calibration, please perform test at room temperature: 18 to 25°C (64.5 to 77.0°F).
• Turn the meter on by pressing ON/OFF.
• When the LCD displays “724”, it is ready.
• Enter the calibration mode by holding CAL
CHECK
for three seconds.
• The date of the last calibration appears (e.g.:
month “01”, day “08”). “F.CAL” means that
the factory calibration is selected.
or
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GENERAL TIPS FOR AN ACCURATE MEASUREMENT
The instructions listed below should be carefully followed during testing
to ensure best accuracy.
• For a correct filling of the cuvet: the liquid in the cuvet
forms a convexity on the top; the bottom of this convexity must be at the same level of the 10 mL mark.
• Proper use of the dropper:
(a) to get good reproducible results, tap the dropper on the table for
several times and wipe the outside of the dropper tip with a
cloth.
(b) always keep the dropper bottle in a vertical position while
dosing the reagent.
• It is important that the sample does not contain any debris. This
would corrupt the reading.
• In order to avoid reagent leaking and to obtain more
accurate measurements, it s recommended to close the
cuvet first with the supplied HDPE plastic stopper and
then with the black cap.
• Each time the cuvet is used, the cap must be tightened to the same
degree.
• Whenever the cuvet is placed into the measurement
cell, it must be dry outside, and completely free of
fingerprints, oil or dirt. Wipe it thoroughly with
HI 731318 (tissue for wiping cuvets, see chapter
“Accessories”) or a lint-free cloth prior to insertion.
(a)
( b
)
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VALIDATION PROCEDURE
Use the validation procedure to ensure that the instrument is properly calibrated.
Warning: do not validate or calibrate the instrument with standard solutions other than the Hanna
CAL CHECK™ Standards, otherwise erroneous results will be obtained. For accurate Validation and
Calibration, please perform test at room temperature: 18 to 25°C (64.5 to 77.0°F).
• Turn the meter on by pressing ON/OFF.
• When the LCD displays “724”, it is ready.
• Place the CAL CHECK™ Standard Cuvet A
into the holder and ensure that the notch on
the cap is positioned securely into the groove.
• Press ZERO and “SIP” will blink on the
display.
• After a few seconds the display will
show “-0.0-”. The meter is now zeroed and
ready for validation.
INTERFERENCES
• Positive error: - Bromine
- Chlorine dioxide
- Iodine
- Ozone
- Oxidized Manganese and Chromium
• Alkalinity above 250 mg/L CaCO3 or acidity above 150 mg/L CaCO3 will not reliably develop
the full amount of color or it may rapidly fade.
To resolve this, neutralize the sample with diluted HCl or NaOH.
• In case of water with hardness greater than 500 mg/L CaCO3, shake the sample for
approximately 2 minutes after adding the powder reagent.
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MEASUREMENT PROCEDURE
• Turn the meter on by pressing ON/OFF.
• When the LCD displays “724”, it is ready.
• Do not let the reacted sample stand too long after reagent is added, or accuracy will be lost.
• It is possible to take multiple readings in a row, but it is recommended to take a new zero
reading for each sample and to use the same cuvet for zeroing and measurement.
• After the reading it is important to discard immediately the sample, otherwise the glass
might become permanently stained.
• All the reaction times reported in this manual are referred to 20°C (68°F). As a general rule
of thumb, they should be doubled at 10°C (50°F) and halved at 30°C (86°F).
• In order to maximize accuracy, prior to a measurement follow the validation procedure to be
sure that the instrument is properly calibrated. If necessary, calibrate the instrument.
• Fill the cuvet with 10 mL of unreacted
sample, up to the mark, and replace the
cap.
• Place the cuvet into the holder and ensure
that the notch on the cap is positioned
securely into the groove.
• Press ZERO and “SIP” will blink on the
display.
• After a few seconds the display will show
“-0.0-”. The meter is now zeroed and
ready for measurement.
• Remove the cuvet.
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• For free chlorine measurement: add 3 drops
of HI 93701A-T DPD1 indicator and 3
drops of HI 93701B-T DPD1 buffer to an
empty cuvet.
Immediately add 10 mL of unreacted
sample. Replace the cap and shake gently.
•
Immediately reinsert the cuvet into the
holder and ensure that the notch on the
cap is positioned securely into the groove.
• Press READ and “SIP” will blink during
measurement.
• The instrument directly displays
concentration in mg/L of free chlorine on
the Liquid Crystal Display.
• Then,
for total chlorine measurement, remove
the cuvet and add to the reacted sample 3
drops of HI 93701C-T DPD3 solution.
Replace the cap and swirl gently.
• Reinsert the cuvet into the holder and
ensure that the notch on the cap is
positioned securely into the groove.
• Wait for 2’ and 30” then press READ and
“SIP” will blink during measurement.
• The instrument directly displays
concentration in mg/L of total chlorine on
the Liquid Crystal Display.
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